Beware warm weather and clear skies; the season of road work is ahead. Four bridges on I-89 in Colchester—76 north and south and 77 north and south, between exits 16 and 17—are scheduled for construction and partial closures from July 19 to Oct. 7.

Built in 1964, the current bridges are 3-span continuous rolled beam bridges, (indicating the space between two supports,) with solid substructures and beams. However, the decks are in poor condition, and the bridge and approach railings do not meet today’s crash standards, according to the Vermont Agency of Transportation (VTrans). The main goals for the project will be to replace the existing bridge decks with new precast deck panels, and to replace the railings.

“We’re trying to make this as painless as possible,” said Todd A. Sumner, VTrans Project Manager, at a public information meeting for the project on April 30. The plan is to finish construction within eleven weeks depending on weather conditions, with construction beginning on 77 and 76 northbound bridges, and then moving onto 77 and 76 southbound.

But Vermont weather doesn’t always cooperate, especially when it’s on a tight schedule. Rain showers or a temperature drop below 40 degrees could put a damper on the laying of concrete, extending the timeline into October or forcing the project to halt for winter and resume in spring. Sumner is hopeful though, suggesting that if weather conditions force the project to miss a weekend closure, there is some wiggle room in the schedule.

While laying concrete and precast deck panels can be riveting, perhaps most immediately relevant to commuters and citizens of Colchester is how this construction will affect traffic on I-89 and Bay Road, below Bridge 76. Scott E. Burbank, VHB Design Project Manager, emphasized the importance of traffic phasing and how they plan to prevent congestion on the highway.

According to Burbank, 1,200 is the “magic number”. During peak times, 1,200 vehicles per hour commute along I-89, with the heaviest morning traffic commuting south, and heaviest evening traffic going north. Instead of reducing to two lanes in each direction during weekdays, Burbank explained, the use of crossover lanes should prevent congestion from piling up. This means that one lane will cross over the bridge onto the other side, in order to keep two lanes open in the busiest direction—southbound in the morning and northbound in the evening. On weekend closures, the same crossover method will be used to divert traffic from construction but only to two lanes, one northbound and one southbound, from Fridays at 7 p.m. to Mondays at 6 a.m.

“The number one rule for construction is, ‘don’t demo over live traffic’,” Burbank said, as discussion at the Public Meeting began to die down.

“Chicken,” replied Sumner from his seat, eliciting dry chuckles from around the room.

In addition to the partial closures on I-89, Bay Road will be closed twice, as well as the bike path on the south side of Bay Road. When Bridge 76 is demoed, Bay Road will alternate one-way, using flaggers. To avoid Bay Road at this time, there will be signs posted for a detour route via Route 2/7 to Blakely Road/VT 127 to East Lakeshore Drive, and then back to Bay Road.

Sumner clarified that the Colchester Triathlon on July 28th will not be affected by the road or bike path closures. There will also be no construction during the Fourth of July holiday.

A separate project in May 2020 is tentatively planned should construction run smoothly this fall, wherein the bridges will be paved, the lines painted, and the steel beams painted.

For weekly construction updates, traffic alerts, and other project information, you can visit vtrans.Vermont.gov/projects/Colchester-i-89-bridges or call the 24-hour hotline 802-595-4399.